The goal of this thesis proposal is to elucidate the function of auditory neurons in the cochlear nucleus (CN) and central nucleus of the inferior colliculus (CNIC). A first step toward understanding function is to find out what stimuli the neuron responds to, ideally without a priori assumptions. Thus, Aim 1 is to develop a method for estimating the spectrotemporal weighting functions (STWFs) of single auditory neurons with pseudorandom noise stimuli. The STWF, or weights that a neuron assigns to sound energy at certain times and frequencies, can be directly applied to predict linear, or nearly linear, neural responses to arbitrary stimuli. Aim 2 is to estimate the STWFs of neurons in the CN of the decerebrate cat, and use local injection of agents that block inhibitory inputs to determine how these STWFs are shaped by inhibition. Aim 3 is to extend the method to include binaural spectrotemporal interactions when estimating weighting functions in the CNIC of the decerebrate cat. Together, experiments of these aims will increase understanding of circuitry and function in the CN and CNIC, and will in turn suggest how hearing impairment and other auditory disorders affect processing of speech and other complex sounds.